A perforating string includes one or more perforating guns, a setting tool, and a plug. The perforating guns may each include a switch having at least two positions. For example, when the switch in an “upper” perforating gun in the perforating string is in the first position, the switch may connect a computing system at the surface to a switch in a “lower” perforating gun in the perforating string. When the switch in the upper perforating gun is in the second position, the switch may cause a detonator in the upper perforating gun to detonate an explosive charge.
When the switch in the lower perforating gun is in the first position, the switch may connect the computing system to a switch in the setting tool, which may be used to set the plug. When the switch in the lower perforating gun is in the second position, the switch may cause a detonator in the lower perforating gun to detonate an explosive charge. Thus, as may be seen, multiple switches are used during the operation of the perforating string. However, as the number of switches in the perforating string increases, so to do the odds that an electrical failure may occur downhole.